The Extinction of an Aversion: Role of the Interval between Non-Reinforced Presentations of the Averted Stimulus

Abstract

A toxiphobia conditioning paradigm was used to examine the relation between the intertrial interval (ITI) and the extinction of an aversion. The design employed was based upon that developed by Davis (1970) to study the relation between the ITI and the habituation of a response. After conditioning, the conditioned stimulus (CS) was presented on two occasions at times T1 and T2, and this interval (the ITI) was varied across groups. However, the interval from the CS exposure at T2 to the extinction test was common for all groups. On the test, ITIs of 6 to 24 hr were found to have promoted more extinction than ITIs of 0.5 hr with odour (Experiments 1a and b) and flavour (Experiment 1c) CSs. Further, this facilitation of extinction by the long ITIs compared to the short ones was not due to differences in the intervals between the initial CS exposure at T1 and the test (Experiment 2). The final experiment examined the relation between the ITI and extinction when different CSs were presented at T1 and T2. A short interval between the presentation of CS1 at T1 and the presentation of CS2 at T2 was found to have facilitated the extinction of the aversion to CS2 compared either to a long interval between these presentations or to the presentation of CS2 in the absence of a prior CS1 presentation. The results were discussed in terms of the model developed by Wagner (1981).

Spacing extinction trials alleviates renewal and spontaneous recovery

“…Westbrook et al (1985) found that a long ITI between extinction trials (spaced) produced more long-term loss of a conditioned taste aversion than did a short ITI (massed). However, massed presentations during extinction facilitated the rate of extinction observed during the extinction treatment.…”

“…This prediction has also received support in the literature. Westbrook, Smith, and Charnock (1985) observed, in a taste-aversion preparation, better extinction after two nonreinforced exposures when these were separated by 24 h, relative to separation by 30 min. In other words, they saw a benefit of conducting an extinction treatment with spaced trials, and, as opposed to Rescorla and Durlach (1987), they did not confound the total amount of exposure to the context, since the interval between extinction trials was spent outside the conditioning boxes.…”

“…We followed the lead of Westbrook et al (1985) and equated context exposure while comparing massed and spaced extinction trials. Under these circumstances, it is possible to isolate the mechanisms responsible for these discrepant findings without appealing to differential exposure to the context as a contributor to the effect of the extinction treatment.…”

Extinction of Conditioned Responses to Methamphetamine-Associated Stimuli in Healthy Humans

“…Therefore, the ‘short’ and ‘long’ ISI intervals reported here may not be analogous to massed and spaced extinction, respectively. Regardless of these definitional differences, the literature concerning massed vs spaced extinction is mixed (see Li and Westbrook 2008; Rescorla and Durlach, 1987; Westbrook, et al 1985). For example, a human study examining extinction of cue-induced drug craving in MA-dependent individuals (Price et al 2010) found that short extinction ISIs (e.g., ≤ 4 days) produced slightly less extinction than longer ISI (e.g., ≥ 4 days).…”

Stepping back from ‘persistence and relapse’ to see the forest: Associative interference

“…In contrast, increased trial spacing during phase 1 target training ordinarily makes the target association more resistant to interference. The enhanced extinction observed when extinction trials are widely spaced occurs readily under most circumstances and also reduces spontaneous recovery and renewal (Urcelay, Wheeler, & Miller, 2009; Westbrook, Smith, & Charnock, 1985). Of course, this depends to a degree on when one assesses learning, considering that massed trials do provide faster emergence of, but less persistent, behavior reflecting the training (Barela, 1999, Teichner, 1952), which appears to hold for extinction treatment as well as excitatory conditioning.…”